Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Tragofone - White-label VoIP Softphone with WebRTC and Auto-provisioning
Notion - All-in-one workspace. One tool for your whole team. Write, plan, and get organized.
tSIP - tomeko.net/software: SIP client for Windows.
Slack - A messaging app for teams who see through the Earth!
Lingo - Empower Creation and Ensure Brand Consistency. Build and Share libraries of visual assets with your entire team — all from your desktop.